Kubernetes YAML Validator – Free Online K8s Manifest Checker

How to Kubernetes YAML Validator Online

1. 1

   Paste your Kubernetes YAML manifest into the input editor, or upload a .yaml file.

2. 2

   Select the target Kubernetes version to validate against the corresponding API schema.

3. 3

   The tool automatically analyzes your manifest for YAML syntax errors and Kubernetes schema compliance.

4. 4

   Review the validation results: syntax errors are highlighted line-by-line, and best-practice warnings (like missing resource limits) are listed below.

5. 5

   Click "Fix Indentation" to automatically correct common YAML formatting issues, or "Copy" to take your valid manifest to your cluster.

Kubernetes YAML Validator Features

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  K8s Schema Validation: Checks your manifests against official Kubernetes OpenAPI specifications for specific versions.

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  Multi-Document Support: Validates files containing multiple Kubernetes resources separated by the standard "---" delimiter.

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  Best Practice Audits: Identifies missing CPU/memory limits, missing health probes (liveness/readiness), and insecure security contexts.

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  Real-time Linting: Catches YAML syntax errors like improper indentation, tab characters, and duplicate keys as you type.

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  Resource Detection: Automatically identifies the resource kind (Deployment, Service, Ingress, etc.) and applies the correct validation rules.

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  Security Scanning: Flags containers running as root or with privileged access to help you maintain a secure cluster.

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  Zero Server-Side Storage: Your YAML manifests are processed entirely in your browser; we never store or transmit your sensitive configuration data.

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  Version Switching: Easily test if your manifest is compatible with different Kubernetes versions (e.g., v1.29 vs v1.31).

Frequently Asked Questions

What is the difference between a YAML linter and a Kubernetes validator?

A standard YAML linter only checks for structural correctness (syntax). A Kubernetes validator goes further by performing semantic validation—checking if the fields, values, and structure match the specific requirements of the Kubernetes API.

Why does my valid YAML fail in Kubernetes?

This usually happens because of semantic errors that a standard linter misses, such as using a field that doesn't exist in a specific API version, type mismatches (e.g., a string where an integer is expected), or missing required fields like "selector" in a Deployment.

Is it safe to paste my Kubernetes Secrets into this tool?

Yes. This tool performs all validation locally in your browser using JavaScript. Your manifest data is never sent to our servers, ensuring your sensitive configuration and Secrets remain private.

Does this tool support Helm templates or Kustomize?

It validates rendered YAML. To check Helm or Kustomize files, you should first run "helm template" or "kubectl kustomize" and then paste the resulting output into this validator.

How do I fix "mapping values are not allowed here" errors?

This is a common YAML indentation error. It usually means you have a colon (:) followed by content on the same line that shouldn't be there, or your indentation level for a child property is incorrect.

Can I validate multiple resources at once?

Yes, the validator supports multi-resource YAML files. Ensure each resource is separated by the standard triple-dash (---) separator.

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